This invention relates generally to confocal microscopy and more specifically to a confocal scanning microscope usable with visible and ultraviolet (UV) light.
Fluorescent light microscopy is extensively used in biological research and medical diagnosis. It provides the selectivity necessary to enable specific components of a cell or tissue to be visualized and the spatial organization of such components to be determined. Confocal microscopy operates so that illumination and detection are confined to a single point in the sample. This is typically achieved by using spatial filters (usually pinholes) in the optical paths of the objective and condenser, and a complete image is built up by sequentially scanning all points in the field of view.
A particular confocal microscope is shown in U.S. Pat. No. 5,032,720, the disclosure of which is incorporated by reference. The microscope produces a small (preferably diffraction limited) spot on a sample, scans the spot over the sample in a raster pattern, and generates an electrical signal proportional to the intensity of light emanating and collected from the region of the spot. The electrical signal is communicated to a computer which can produce a visual display on the monitor.
The optical train between the source (or detector) and the sample comprises focusing optics to form the spot and scanning elements to scan the beam in two orthogonal directions to form the raster pattern on the sample. The light emanating from the sample passes along a return path to a detector, which generates the electrical signal. An aperture in the form of an iris diaphragm is disposed in front of the detector and blocks light that emanated from points spatially displaced from the beam spot.
A confocal microscope accessory for use in combination with a conventional microscope has been marketed under the trade designations MRC-500 and MRC-600 by Bio-Rad Laboratories, Inc., Hercules, California. The resulting confocal microscope provides a visible excitation beam and senses fluorescence in the visible range.